000 AXNT20 KNHC 232351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI NOV 23 2012 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF GUINEA AT 9N13W TO 8N15W. THE ITCZ BEGINS AT 8N15W AND CONTINUES ALONG 6N22W 7N30W 5N42W 5N54W. SCATTERED STRONG CONVECTION IS FROM 6N-9N BETWEEN 15W-24W WITH SCATTERED MODERATE/ISOLATED STRONG CONVECTION FROM 2N-6N BETWEEN 16W-27W. SCATTERED MODERATE CONVECTION IS FROM 5N-10N BETWEEN 27W-38W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-10N BETWEEN 52W-62W. THIS ACTIVITY IS ALSO NEAR A SURFACE TROUGH EMBEDDED WITHIN THE ITCZ REGION ALONG 10N58W TO 5N58W. ...DISCUSSION... GULF OF MEXICO... MAINLY ZONAL WESTERLY FLOW ALOFT COVERS THE GULF OF MEXICO. WATER VAPOR IMAGERY INDICATES MOSTLY DRY AIR CONTINUES TO COVER THE MAJORITY OF THE BASIN ESPECIALLY THE EASTERN HALF SUPPORTING FAIR SURFACE CONDITIONS. A WEAK SURFACE RIDGE AROUND A 1025 MB HIGH NEAR SE LOUISIANA IS PROVIDING LIGHT ANTICYCLONIC FLOW ACROSS THE AREA WITH SOME STRONGER NORTHERLY WINDS UP TO 15 KT ACROSS THE FAR SE CORNER. HOWEVER...AN UPPER LEVEL TROUGH MOVING THROUGH THE EASTERN CONUS EXTENDING INTO NW MEXICO SUPPORTS A COLD FRONT THAT IS APPROACHING THE TEXAS COAST. AS OF 2100 UTC...THE FRONT WAS JUST ALONG THE COASTLINE AND WILL HAVE EMERGED OFF IT BY 24/0000 UTC. SHOWERS/THUNDERSTORMS ARE ALONG THE FRONTAL BOUNDARY AND WILL IMPACT THE NW GULF SHORTLY. THE FRONT IS EXPECTED TO MOVE QUICKLY THROUGH THE BASIN WITH SURFACE RIDGING BUILDING IN BEHIND IT BY LATE SUNDAY. STRONG NORTH TO NORTHEAST WINDS OF 20-25 KT ARE EXPECTED BEHIND THE FRONT. CARIBBEAN SEA... MOSTLY WEST TO SOUTHWEST FLOW ALOFT COVERS THE CARIBBEAN AROUND A BROAD UPPER LEVEL RIDGE CENTERED JUST EAST OF THE LESSER ANTILLES. WATER VAPOR IMAGERY INDICATES THAT DRY AIR COVERS BOTH THE NW AND FAR EAST CARIBBEAN SUPPORTING FAIR WEATHER WITH MORE MOIST SOUTHWESTERLY FLOW COVERING THE CENTRAL CARIBBEAN. AT THE SURFACE...NORTHERLY FLOW OF 15-20 KT IS ACROSS THE WESTERN CARIBBEAN...WHILE LIGHTER AND EASTERLY WINDS OF 10-15 KT COVER THE CENTRAL AND EASTERN CARIBBEAN FORMING SURFACE CONVERGENCE NEAR A SURFACE TROUGH IN THE CENTRAL CARIBBEAN FROM HISPANIOLA NEAR 18N70W TO NORTHERN COLOMBIA AT 12N73W. THE COMBINATION OF SURFACE CONVERGENCE NEAR THE TROUGH ALONG WITH MOIST SOUTHWESTERLY FLOW ALOFT IS HELPING PRODUCE SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 9N-12N BETWEEN 73W-81W WITH WIDELY ISOLATED SHOWERS CONTINUING NORTHWARD TO HISPANIOLA. THE MONSOON TROUGH...WITH AXIS JUST NORTH OF PANAMA...MAY ALSO BE PLAYING A ROLE IN THE ACTIVITY IN THE SW CARIBBEAN. A DISSIPATING STATIONARY FRONT IN THE ATLC EXTENDS TO NORTHERN HISPANIOLA PRODUCING A FEW ISOLATED SHOWERS ACROSS THE ISLAND AS WELL AS AHEAD OF IT ACROSS PUERTO RICO. EXPECT LITTLE CHANGE OVER THE NEXT 24 HOURS. ATLANTIC OCEAN... THE SYSTEM IN THE WEST ATLC HAS FINALLY SIMPLIFIED WITH ONLY A SINGLE 993 MB SURFACE LOW CENTER EXISTING NEAR 35N64W. THE LOW IS PRODUCING SEVERAL SURGES OF STRONG WINDS AND COOLER AIR. A DISSIPATING STATIONARY FRONT IS FARTHEST EAST ALONG 32N58W 26N59W 19N70W. TO THE WEST...A COLD FRONT ENTERS THE AREA NEAR 32N63W 28N64W 23N79W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE EAST OF THE EASTERNMOST FRONT NORTH OF 26N BETWEEN 45W-56W...AND FROM 21N-26N BETWEEN 55W-60W. A FEW ISOLATED SHOWERS ARE ALSO NEAR THE FRONT AXIS NEAR HISPANIOLA. THE LACK OF SHOWERS NEAR THE FRONTAL BOUNDARIES IS MAINLY DUE TO THE FACT THAT DRY AIR HAS WRAPPED AROUND THE UPPER LEVEL LOW SUPPORTING THE SYSTEM EXCEPT FAR TO THE EAST WHERE DIFFLUENCE EXISTS BETWEEN THE BROAD UPPER TROUGH AND AN UPPER LEVEL RIDGE OVER THE CENTRAL ATLC. THE UPPER RIDGE SUPPORTS A WEAK SURFACE RIDGE AROUND A 1018 MB HIGH NEAR 27N41W. A BROAD UPPER TROUGH OVER THE EASTERN ATLC SUPPORTS A WEAK SURFACE TROUGH ALONG 32N21W TO 25N35W. POSSIBLE ISOLATED SHOWERS ARE NEAR THE AXIS. THE TROUGH BISECTS THE SURFACE RIDGE ALLOWING FOR A SECOND HIGH CENTER TO THE EAST OF THE TROUGH AXIS CENTERED NEAR 26N21W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON